Cadmium exposure and atherosclerotic carotid plaques--results from the Malmö diet and Cancer study.

Epidemiological studies indicate that cadmium exposure through diet and smoking is associated with increased risk of cardiovascular disease. There are few data on the relationship between cadmium and plaques, the hallmark of underlying atherosclerotic disease. To examine the association between exposure to cadmium and the prevalence and size of atherosclerotic plaques in the carotid artery. A population sample of 4639 Swedish middle-aged women and men was examined in 1991-1994. Carotid plaque was determined by B-mode ultrasound. Cadmium in blood was analyzed by inductively coupled plasma mass spectrometry. Comparing quartile 4 with quartile 1 of blood cadmium, the odds ratio (OR) for prevalence of any plaque was 1.9 (95% confidence interval 1.6-2.2) after adjustment for sex and, age; 1.4 (1.1-1.8) after additional adjustment for smoking status; 1.4 (1.1-1.7) after the addition of education level and life style factors; 1.3 (1.03-1.8) after additional adjustment for risk factors and predictors of cardiovascular disease. No effect modification by sex was found in the cadmium-related prevalence of plaques. Similarly, ORs for the prevalence of small and large plaques were after full adjustment 1.4 (1.0-2.1) and 1.4 (0.9-2.0), respectively. The subgroup of never smokers showed no association between cadmium and atherosclerotic plaques. These results extend previous studies on cadmium exposure and clinical cardiovascular events by adding data on the association between cadmium and underlying atherosclerosis in humans. The role of smoking remains unclear. It may both cause residual confounding and be a source of pro-atherogenic cadmium exposure.